相关论文: Framework Flexibility and the Negative Thermal Exp…

We use a symmetry-motivated approach to analysing X-ray pair distribution functions to study the mechanism of negative thermal expansion in two ReO$_3$-like compounds; ScF$_3$ and CaZrF$_6$. Both average and local structure suggest that it…

Many ceramic and hybrid metal-organic framework materials show negative thermal expansion (NTE): they \textit{contract} instead of expanding on heating \cite{Barrera_Miller_Lind_Romao 2005}. Their structures are invariably characterised as…

The negative thermal expansion (NTE) effect has been found generally combined with structural phase transitions. However, the charge and orbital freedoms of the NTE has not been well studied. This study employs angle-resolved photoemission…

Negative thermal expansion (NTE) - the phenomenon where some materials shrink rather than expand when heated - is both intriguing and useful, but remains poorly understood. Current understanding hinges on the role of specific vibrational…

The thermal expansion behavior of metal fluorides can be tuned by choosing appropriate metal cation. We present ab-initio lattice dynamical studies on the metal fluorides (CaZrF6, MgZrF6 and SrZrF6) and identify the anharmonic phonon modes…

We have devised an isotropic interaction potential that gives rise to negative thermal expansion (NTE) behavior in equilibrium many-particle systems in both two and three dimensions over a wide temperature and pressure range (including zero…

Origin and composition dependence of the anisotropic thermomechanical properties are elucidated for Ba1-xSrxZn2Si2O7 (BZS) solid solutions. The high-temperature phase of BZS shows negative thermal expansion (NTE) along one crystallographic…

While most solids expand when heated, some materials show the opposite behavior: negative thermal expansion (NTE). In polymers and biomolecules, NTE originates from the entropic elasticity of an ideal, freely-jointed chain. The origin of…

Minimal models are developed to examine the origin of large negative thermal expansion (NTE) in under-constrained systems. The dynamics of these models reveals how underconstraint can organize a thermodynamically extensive manifold of…

Ca2RuO4 is a structurally-driven Mott insulator with a metal-insulator transition at TMI = 357K, followed by a well-separated antiferromagnetic order at TN = 110 K. Slightly substituting Ru with a 3d transition metal ion M effectively…

We have investigated temperature dependence of the lattice parameters and the unit cell volume of ZnF$_2$ by neutron diffraction and have discovered negative thermal expansion (NTE) at low temperature. To understand why this simple compound…

We discovered unique uniaxial negative thermal expansion (NTE) behavior for a weak-itinerant-ferromagnetic phase of CoZr$_{2}$H$_{3.49}$. CoZr$_{2}$ is known as a superconductor exhibiting uniaxial NTE along the $c$-axis, which is called…

The discovery of unusual negative thermal expansion (NTE) provides the opportunity to control the common but much desired property of thermal expansion, which is valuable not only in scientific interests but also in practical applications.…

Ca2RuO4 undergoes a metal-insulator transition at TMI = 357 K, followed by a well-separated transition to antiferromagnetic order at TN = 110 K. Dilute Cr doping for Ru reduces the temperature of the orthorhombic distortion at TMI and…

We report physical and structural properties of single-crystal Ca2Ru1-xFexO4 (0<x<0.20) as functions of temperature, magnetic field and pressure. Ca2RuO4 is a structurally-driven Mott insulator with a metal-insulator (MI) transition at TMI…

We report on negative thermal expansion (NTE) in the high-field, half-magnetization plateau phase of the frustrated magnetic insulator CdCr2O4. Using dilatometry, we precisely map the phase diagram at fields of up to 30T, and identify a…

Recently, uniaxial negative thermal expansion (NTE) has been observed in transition-metal zirconides including tetragonal (CuAl2-type) CoZr2 and orthorhombic (Re3B-type) CoZr3. Here, we report the observation of uniaxial NTE in tetragonal…

Thermally-densified hafnium terephthalate UiO-66(Hf) is shown to exhibit the strongest isotropic negative thermal expansion (NTE) effect yet reported for a metal-organic framework (MOF). Incorporation of correlated vacancy defects within…

This study examines the temperature-dependent evolution of the lattice constants for various CuAl2-type compounds, including NiZr2, (Co,Rh,Ir)Zr2, (Fe,Co,Rh,Ir)Zr2, and (Co,Ni,Cu,Rh,Ir)Zr2, in the pursuit of negative or zero thermal…

Magnetism-induced negative thermal expansion (NTE) observed in inverse perovskite antiferromagnets Mn3AN (A=Zn, Ga, etc.) is theoretically studied by a classical spin model with competing bond-length-dependent exchange interactions. We…